RFC 3597, "Handling of Unknown DNS Resource Record (RR) Types", September 2003Source of RFC: dnsext (int)
See Also: RFC 3597 w/ inline errata
Errata ID: 1063
Publication Format(s) : TEXT
Reported By: Peter Koch
Date Reported: 2005-09-13
Verifier Name: Brian Haberman
Date Verified: 2012-05-01
Section 7 says:
As a courtesy to implementors, it is hereby noted that the complete set of such previously published RR types that contain embedded domain names, and whose DNSSEC canonical form therefore involves downcasing according to the DNS rules for character comparisons, consists of the RR types NS, MD, MF, CNAME, SOA, MB, MG, MR, PTR, HINFO, MINFO, MX, HINFO, RP, AFSDB, RT, SIG, PX, NXT, NAPTR, KX, SRV, DNAME, and A6.
It should say:
Compare with RFC 4034 (section 6.2):
"3. if the type of the RR is NS, MD, MF, CNAME, SOA, MB, MG, MR, PTR,
HINFO, MINFO, MX, HINFO, RP, AFSDB, RT, SIG, PX, NXT, NAPTR, KX,
SRV, DNAME, A6, RRSIG, or NSEC, all uppercase US-ASCII letters in
the DNS names contained within the RDATA are replaced by the
corresponding lowercase US-ASCII letters;"
Almost exactly the same list. One HINFO too much is no issue,
but if this actually should be TXT it's a real typo.
neither TXT nor HINFO contain domain names in RDATA, so it's a bug in both
RFC 3597 and 4034, although one that doesn't hurt. One could also argue that the list lacks NSAP-PTR, but then that's as obsolete as MD ans MF.